A Korea-UK team (contact Myungshik Kim, Queen's University, Belfast, m.s.kim@qub.ac.uk, or Chilmin Kim, Paichai University) has introduced a method for preventing several clever attacks against quantum cryptography, a form of message transmission that uses the laws of quantum physics to make sure an eavesdropper does not covertly intercept the transmission. Making the message sender and receiver a little blind to each other's actions, the researchers have shown, can bolster their success against potential eavesdroppers.

In quantum cryptography, a sender (denoted as Alice) transmits a message to a receiver (called Bob) in the form of single photons each representing the 0s and 1s of binary code. If an eavesdropper (appropriately named Eve) attempts to intercept the message, she will unavoidably disturb the photon through the Heisenberg uncertainty principle, which says that even the gentlest observation of the photon will perturb the particle. This will be instantly detectable by Alice and Bob, who can stop the message and start again. Quantum cryptography is already being used in the real world and is even available commercially as a way for companies to transmit sensitive financial data.